Alongside the dangerous roads as those by the coast or those in the mountains and highways or freeways, road railing of various height and size, according to the necessity of the design of the roads, have to be set up to ensure the safety of driving by way of preventing cars from crashing with those in the opposite direction or from falling down the cliffs and thereby minimize casualties resulted from driving accidents.
The road railing adopted widely now comprises of pillars, with their lower part made of steel bars and cement, being fixed underground and rails, in parallel horizontally to road surface, connecting the pillars.
The road railing which bears the function to minimize casualties resulted from driving accidents is subject to frequent damage that necessitates repair which, if undertaken in traditional way, is indeed troublesome and time-wasting in that cement remained attaching to the steel bars of the damaged pillars has to be clear away first, and those bent steel bars of the damaged pillars have to be straightened thereafter, and wooden boards have to be set up around those straightened steel bars thereafter, and cement has to be poured into the area surrounded by wooden boards in order to have the repaired or new pillars fixed underground thereafter, and ten to twenty days have to be spent on waiting for the cement to become dry thereafter, and those wooden boards will be removed and pillars connected with rails at last.
Since much time has to be spent on repairing those damaged pillars and part of the road blocked during the repair, traffic jam can hardly be avoided and the possibility of traffic accident will be increased.
Furthermore, that kind of fixed road railing cannot be guaranteed to carry out its function well after a certain period of time as the road will be asphalted, if necessary, in order to maintain a good condition of the road surface and thereby, though the road base will be consolidated, the standard in height of the road railing, (for instance, must be 85 cm above the road surface), will be lowered.